PURPOSE:To aim at enhancing the riding comfort and maneuvering stability of a vehicle having a stabilizer bar and an air suspension, by determining whether a stabilizer bar controlling cylinder can be extended and retracted or not in accordance with the charge and discharge of pressurized air to and from the suspension. CONSTITUTION:Pressurized air is fed from an accumulator Q into an air chamber R in an air suspension 1 to extend and retract the air suspension 1 and to operate an actuator (a), and accordingly the height of a vehicle and damping force are adjusted. Simultaneously, the charge and discharge of pressurized air to and from the accumulator Q effect a pilot pressure for an operation check valve 3 so as to determine whether a cylinder 2 for controlling a stabilizer bar S can be extended and retracted or not. That is, the check valve 3 is opened when the pilot pressure is effected, but is closed when no pilot pressure is effected, and accordingly, the characteristic of the stabilizer bar S is adjusted. With this arrangement, it is possible to the enhance the riding comfort and maneuvering stability of the vehicle.